For varying values of “then” ranging from the 1870s through the 1890s to the 1950s.
Chandonnet, Ann. Gold Rush Grub: From Turpentine Stew to
Hoochinoo. 2005, University of Alaska Press. Recipes and stories, and what the heroine of True Gold had to deal with to get food on the table.
Moulton, Candy. The Writer’s Guide to Everyday Life in the Wild West, from 1840-1900. 1999, Writer’s Digest Books. A good basic guide, with many references.
Reynolds, Edward B. and Michael Kennedy. Whistleberries, Stirabout, and Depression Cake: Food Customs and Concoctions of the Frontier West. 2000, Falcon Publishing. A reprint of parts of a Federal Writers’ Project book from the 1930s. Recipes and tales.
Steele, Volney. Bleed, Blister, and Purge: A History of Medicine on the American Frontier. 2nd edition, 2005, Mountain Press Publishing Company. Not to be read by anyone with a weak stomach. But it sure did help me figure out how to kill off a character once, and probably will again.
Swell, Barbara. Log Cabin Cooking: Pioneer Recipes and Food Lore. 1996, Native Ground Music, Inc. Some of it is before my time period, but it explains cookery under, well, primitive circumstances.
http://www.foodtimeline.org/index.html Useful for not putting food that didn’t exist yet into the mouths of my characters. Also for disappointing my time traveling hero.
http://www.ssa.gov/OACT/babynames/ I almost gave a spear
carrier a name that wasn’t used for girls in her time. This Social
Security Administration site saved me the anachronism. Also a good resource on the rare occasion when a character does not arrive in my brain complete with name.
http://www.fashion-era.com/index.htm What the properly dressed hero and heroine were wearing in the 1870s. Or the 1890s. Or the 1950s, for that matter. I checked many, many books about historical clothing out of the library, but this site really helped cut through the clutter.
http://www.thepeoplehistory.com/ doesn’t go back far enough, but it was useful for popular culture in the 1950s, so I didn’t put the wrong anachronisms in my hero’s mouth or on his body, at any rate.
http://www.nwhp.org/ is an essential resource for an often-
neglected part of history, the part where women starred.